Shionogi & Co. forecast that its experimental treatment peramivir will earn annual sales of about ¥5 billion in Japan on demand from hospitals for patients critically ill with influenza, including swine flu.

Shionogi plans to file data to the health ministry in November for approval to market the flu medication and expects to sell it as early as October next year, Takuko Y. Sawada, head of development at the Osaka-based company, said in an interview.

If approved, peramivir would compete with antiviral drugs such as Roche Holding AG's Tamiflu and GlaxoSmithKline PLC's Relenza. Sawada said peramivir, which has completed all three typically required trial stages, is administered directly into the bloodstream, allowing it to take effect more rapidly.